1. Field of the Invention
The present invention relates to a clothes dryer, and more particularly, to an apparatus for driving a drum of a clothes dryer.
2. Description of the Conventional Art
Generally, a clothes dryer is separately installed from a washing machine thereby to automatically dry wet clothes that has completed a washing operation. According to a drying method, the clothing dryer can be divided into a condensation type and an exhaust type.
The condensation type clothing dryer is provided with a heat exchanger for condensing moisture included in air that has passed through a drum therein. The condensation type clothing dryer circulates air therein thus to discharge condensed water outwardly, and heats dry air by a heater thus to supply into the drum, thereby drying clothes inside the drum.
The exhaust type clothing dryer sucks external air, heats the sucked air by a heater thus to introduce into a drum, and discharges air that has passed through the drum outwardly, thereby drying clothes inside the drum.
As shown in FIG. 1, the conventional exhaust type clothing dryer comprises: a cabinet 10 having an inlet 10a for introducing clothes and a door 11 for opening and closing the inlet 10a at a front side thereof; a drum 12 rotatably installed in the cabinet 10 and for accommodating clothes therein; an air circulation device 15 for sucking external air into the cabinet 10 thereby introducing into the drum 12, and discharging air that has passed through the drum 12 to outside of the cabinet 10; a heater 16 for heating air introduced into the drum 12; and a drum rotation device 14 for rotating the drum 12.
The air circulation device 15 includes: a suction port 15a formed at a rear upper side of the cabinet 100, for sucking external air into the cabinet 10; a suction duct 15b respectively connected to inside of the cabinet 10 and an opening portion 12b formed at a rear side of the drum 12, for introducing air that has been sucked into the cabinet 10 into the drum 12; a fan 15c installed at the suction duct 15b and rotated, for sucking external air and thereby generating a suction force to introduce the sucked air into the drum 12; and an exhaust duct 15d connected to an opening portion 12a formed at a front side of the drum 12, for discharging air that has passed through the drum 12 to outside of the cabinet 10.
The heater 16 is installed in the suction duct 15b thereby to heat air introduced into the drum 12 after passing through the suction duct 15b. 
The drum rotation device is composed of: a driving motor 13 arranged at one side of the drum 12 and generating a rotational force; a pulley 14a installed at a rotational shaft of the driving motor 13; and a belt 14b installed to cover outer circumferences of the drum 12 and the pulley 14a, for transmitting a rotational force of the driving motor 13 to the drum 12. The driving motor 13 is also connected to the fan 15c thereby to rotate the fan 15c. 
In the conventional clothes dryer, when the driving motor 13 and the heater 16 are operated, the drum 12 connected to the driving motor 13 through the pulley 14a and the belt 14b is rotated thereby to stir clothes accommodated in the drum 12. As the driving motor 13 is rotated, the fan 15c is operated and thereby external air is sucked into the cabinet 10 through the suction port 15a. The sucked air is introduced into the suction duct 15b and is heated by the heater 16 thus to be introduced into the drum 12.
The air of high temperature that has been introduced into the drum 12 deprives moisture of the clothes inside the drum 12, and the air including the moisture is discharged outside the cabinet 10 through the exhaust duct 15d. According to this, the wet clothes inside the drum 12 is dried.
However, in the conventional clothes drier, the drum 12 is rotated as a driving force of the driving motor 13 is transmitted to the drum 12 through the belt 14b. According to this, the belt 14b is easily worn away thus to be damaged, and a slip is generated between the belt 14b and the drum 12. Therefore, the drum 12 is not smoothly rotated thus to damage the clothes inside the drum 12 by the air of high temperature.
Also, since the drum 12 has to be completely separated from the cabinet 10 in order to replace the belt 14b, the replacement process is very complicated.